The Tissue-Reconstructing Ability of Colon CSCs Is Enhanced by FK506 and Suppressed by GSK3 Inhibition

Abstract

Cancer stem cells (CSC) are capable of reconstructing cancer tissues, are involved in both recurrence and metastasis, and contribute to therapeutic resistance. Therefore, elucidating the molecular mechanism in CSCs is important to successfully treat unresectable cancers. Previously, we observed that colon cancer stem-like cells can be induced from human colon cancer cell lines by retrovirally introducing OCT3/4, SOX2, and KLF4, and we have designated such cells as induced cancer stem cells (iCSC). In the current study, we used iCSCs to evaluate the molecular mechanism of colon CSCs and developed new methods to control them. The spheres that were derived in vitro from the iCSCs, but not those from parental cells, mimicked human colon cancer tissues in terms of their immunohistologic patterns; therefore, sphere-forming ability was assessed as a measure of the tissuereconstructing ability of iCSCs. Interestingly, the calcineurin inhibitor FK506 enhanced the sphere-forming ability of iCSCs, whereas GSK3 inhibition by RNAi, CHIR99021, and valproic acid (VPA) impeded the sphere-forming ability and expansion of iCSCs. FK506 and GSK3 inhibition showed the opposite effect regarding the NFATc3 localization of iCSCs. These data reveal the crucial role that NFAT localization, as regulated by calcineurin and GSK3, plays in the tissue-reconstructing ability of colon cancer stem cells and the potential of GSK3 inhibitors, such as VPA, in colon cancer stem cell-targeting therapy.

MeCP2 Promotes Colorectal Cancer Metastasis by Modulating ZEB1 Transcription

“…The expression of a downstream target gene of ZEB1, MMP14 (a matrix metalloprotease), was also consistently suppressed in MeCP2-depleted HCT116 cells ( Figure 5C). Moreover, the expression of cancer stem cell surface antigens, including CD133 (Prominin-Like Protein 1) [21], KLF4 (Kruppel-like factor 4) [22], and Sox2 (SRY-Related HMG-Box Gene 2) [23], was reduced after MeCP2 inhibition ( Figure 5C), consistent with the aforementioned observations in the sphere formation assay. Expression of full-length MeCP2 restored ZEB1 mRNA expression in MeCP2-depleted cells ( Figure 5D left), but truncated or mutated versions of MeCP2 (Table S5, the sequence of wild type or depletion MeCP2 CDS) had no effect ( Figure 5D right).…”

Glycogen Synthase Kinase 3β in Cancer Biology and Treatment

“…It was also reported that GSK3β inhibitors suppress Bcl2-mediated and α5/β1-integrin-dependent cell survival pathways, thereby eliminating primitive leukemia progenitor/stem cells [134,137,138]. Other studies have implicated different mechanisms for the effects of GSK3β inhibition on CSCs from colorectal, head and neck and prostate cancer [42,49,76,92]. In contrast to the role of GSK3β in CSCs, previous studies have indicated that GSK3β inhibition is essential for maintaining the "stemness" phenotype in embryonic and hematopoietic SCs.…”

“…To date, the tumor-promoting functions of deregulated GSK3β have been reported in 25 cancer types from various organs and tissues across the body ( Table 1 ) [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ...…”

“…It was also reported that GSK3β inhibitors suppress Bcl2-mediated and α5/β1-integrin-dependent cell survival pathways, thereby eliminating primitive leukemia progenitor/stem cells [ 134 , 137 , 138 ]. Other studies have implicated different mechanisms for the effects of GSK3β inhibition on CSCs from colorectal, head and neck and prostate cancer [ 42 , 49 , 76 , 92 ].…”

Growth inhibitory efficacy of natural products in a model for triple negative molecular subtype of clinical breast cancer

“…These transcription factors are also essential for the induction of pluripotent stem cells derived from adult somatic cells (44)(45)(46)(47). The experiments presented in Fig.…”